Sequence Impedance Model and Resonance Damping of Voltage Source based DFIG

When a voltage-source based doubly fed induction generator (DFIG) wind power system is connected to a parallel-compensated weak grid, due to the impedance interaction between the two systems, the problem of medium-high frequency resonance is prone to occur. In order to solve the problem of medium and high frequency resonance and improve the stability of the operation of the voltage-source based DFIG wind power system when connected to the parallel compensation weak grid, this paper proposes an active damping resonance suppression control strategy. First, the harmonic impedance linearization method was used to establish the sequence impedance model of the voltage-source based DFIG. Then, based on the impedance model, the stator current is fed forward into the current inner loop of the generator-side converter in real time, and the combined damping of virtual positive resistance and positive capacitance is used to reshape the DFIG wind power system impedance to achieve medium-high frequencies. Purpose of resonance suppression. Experimental results verify the effectiveness of the proposed DFIG system damping control strategy.